Tetraacetals of glyoxal with glycol monoethers and process of making them



Patented June 8, 1943 UNITED. STATES- PATENT OFFICE:

TETRAACETALS OF GLYOXAL WITH GLY- COL MONOETHERS MAKING THEM AND rnocsss or Louis G. MacDowell, Charleston, and Raymond W. McNamee, South Charleston, W. Va, assignors to Carbide and Carbon Chemicals Corporation, a corporation of New York Y No Drawing.- Application March 18, 1941,

Serial No. 383,928 a "11 Claims. (Cl. 260-615) This invention relates to glyoxal tetra-acetals oi glycol mono-ethers, comprising both monoglycol and polyglycol mono-ethers, and it includes processes of making these compounds.

The glyoxal tetra-acetals to which this invention pertains may be represented by the following formula:

'where X is an alkylene group having at least for oils, fats, resins and cellulose derivatives. They may be employed in processes for the extraction of essential oils, as well a alkaloids, and in methods for the removal of wax from hydrocara bons. Lower alkoxyalkyl tetra-acetals of glyoxal, such as glyoxal tetra(met hoxyethyl) acetal, are soluble both in water and in most classes of organic liquids, and they may act as a strong mutual solvent or coupling agent to bring into solution mutually immiscible liquids or to improve drates, polymers, and hydrated polymers.

More specifisuch as hydrochloric and sulfuric acids, as well as mineral acid salts, such as aluminum sulfate or boron trifluoride. Because of the difllculty in handling and storing monomeric glyoxal, the glyoxalpreferably is added in aqueous solution where it exists either in the form of ahydrate I or a hydrated polymer, possibly tetrahydroxy- .dioxane. Thus, the substances employed in this invention to react with glycol mono-ethers to form glyoxal tetra-acetals consist of aqueous glyoxal, as well as monomeric glyoxal, its hy- The invention contemplates the removal of any water initially present as well a that formed in the reaction.

The amount of glycol mono-ether employed in the acetal reaction is preferably more than that stoichiometrically required. Where the glycol mono-ether ls water-immiscible, this may provide'a convenient method for theremoval of the water of reaction wherein-a constant boiling mixthe stability of an emulsion of one such liquid in another. The higher alkoxyalkyl tetraacetals oi glyoxal are insoluble in water and they are excellent plasticizers for cellulose derivatives, for polyvinyl acetal resins, and for casein. Certain or the aromatic derivatives have mild fragrant odors and are useful in periumery.

While 'in some. instances, it may be possible to make the glyoxal tetra-acetals oi the monoglycol and polyglycol mono-ethers by known reactions, such as those involving the use oi glyoxal sul-v phate, we have discovered an efficient method of making these products directly from glyoxal and the glycol mono-ethers. The method of this invention involves heating the glyoxal and glycol mono-ether, preferably in the presence of a small amount of an acidic catalyst, and continuously removing the water of reaction as it is formed.

' Suitable acidic catalysts include mineral acids,

ture. of water and the glycol mono-ether is continuously distilled and the glycol' mono-ether separated from the distillate and returned to the reaction. Carrying out the process under re.- duced pressure will also facilitate removal of the water, especially when'the acetal formed is that of a high boiling l col ether. Irrespective of the solubility in water of the glycol etherinvolved,

the process may be carried out advantageously. in the presence of a volatile, inert, water-immiscible liquid, such as benzene, toluene, xylene, hexane, ethylene dichloride, or isopropyl ether, and the water of reaction can be removed as an azeotropic distillate with this liquid.- This procedure has the advantage of permitting the use of lower reaction temperatures, thus retarding the formation of byproducts. The temperatures required may vary from but slightly elevated temperatures. it low boiling dehydrating agents areemployed, such as ethyl ether, up to temperatures near the boiling point-range of the glyoxal tetra-acetal formed.

The following examples will illustrate the practice of the invention:

Example 1.Four hundred and fifty-five (455) grams of a 51% aqueous glyoxal solution (containing 4 mols of glyoxal) 2,432 grams (32 mols) of the methyl ether of ethylene glycol, and 3 cc. of concentrated sulfuric acid were heated in a distillation kettle. action, as well as that initially present," was removed continuously by straight distillation.

added to neutralize the catalyst and the. excess The water evolved in the re- At the completion of the reaction,-that is, when all Y the water had distilled over, sodium acetate was monobutyl ether of ethylene glycol (4 mols), 0.6

cc. of concentrated sulfuric acid, and 200 cc. of toluene were heated together in a distillation ket-- tle. A constant boiling mixture of water and toluene was distilled o'ver, condensed, and collected in a decanter from which the water layer was removed and the toluene layer returned to the still column as reflux. After about 24 grams of water had been removed, the excess of toluene was distilled off. An 86.2% yield of glyoxal tetra (butoxy-ethyl) acetal was obtained. The major portion or this material boiled at 240 to 250 C. at 4 mm. and possessed a specific gravity of 0.961 at 20 C. It was insoluble in water, sparingly soluble in methanol and completely soluble in all other common organic solvents and in mineral oil.

Modifications or the invention other than those disclosed will be readily apparent to those skilled in the art and are intended to be included within the invention as defined by the appended claims.

We claim:

1. Glyoxal tetra-acetals of glycol mono-ethers. 2. Glyoxal tetra-acetals or glycol mono-alkyl ethers.

3. Glyoxal tetra-acetals of monoglycol monoalkyl others.

4. Glyoxal tetra-acetals of polyglycol monoalkyl ethers.

5. Glyoxal tetra-acetals of ethylene glycol mono-alkyl ethers.

6. Glyoxal tetra (methoxy-ethyl) acetai.

'7. Glyoxal tetra (butoxy-ethyl) acetal.

8. Process of making lyoxal tetra-acetals or glycol mono-others which comprises heating one of the group consisting of aqueous glyoxal, monomeric glyoxal and the hydrates. polymer and hydrated polymers of glyoxal with a glycol monoether and progressively removing the water formed in the reaction. I

9. Process of making glyoxal tetra-acetals' of glycol mono-ethers which comprises heating an aqueous solution of glyoxal with a glycol monoether, removing thewater initially present and progressively removing the water formed inthe reaction.

10. Process of making glyoxal tetra-acetals 01' ethylene glycol mono-alkyl others which comprises heating an aqueous solution or glyoxal with an ethylene glycol mono-alkyl ether, removing the water initially present and progressively removing the water iormed in the reaction, and recovering said glyoxal tetra-acetal from the reac- .tion mixture.

11. Process of making a glyoxal tetra-acetal of an ethylene glycol mono-alkyl' ether which comprises heating one or the group consisting of aqueous glyoxal, monomeric glyoxal and the hydrates, polymers and hydrated polymers of glyoxal with an ethylene glycol mono-alkyl ether in the presence of a small amount of an acidic catalyst and in the presence or an inert, volatile water-immiscible liquid, progressively removing the water formed in the reaction as a constant boiling mixture with said liquid, and recovering said glyoxal tetra-acetal from the reaction mixture.

LOUIS G. MAODOWELL. RAYMOND W. McNAMEE. 

